The present invention relates to a tire uniformity measurement and correction apparatus for measuring uniformity of tires and correcting the uniformity by a grinder mechanism if necessary.
In a uniformity measurement and correction apparatus for tire, a rotary drum used as substitute for a flat road surface is pressed against a tire attached to a rotary shaft, three components of a force occurring when the tire rotates are measured, and a uniformity correction is carried out by scraping a required portion with a grinder mechanism on the basis of the result of the measurement.
The uniformity correction is carried out while the rotary drum is pressed against the tire to carry out a uniformity measurement again after the correction and further carry out a uniformity correction if necessary.
Hitherto, one rotary drum and one grinder mechanism have been provided in combination for one transfer line in general (Japanese Patent Publication Sho 53-14598).
There is an example in which one rotary drum is used in common for two transfer lines, however, when it enters into tire uniformity correction stage, control of uniformity measurement and correction is the same as the case having one rotary drum for one transfer line.
Therefore, if a uniformity correction is commenced at one transfer line, the rotary drum is kept in the state pressed against the corresponding tire to carry out a uniformity measurement again after the correction and the state of the rotary drum pressed against the tire is maintained until an final uniformity measurement is completed after necessary repetition of corrections and measurements during which uniformity measurements are carried out intermittently.
Accordingly, another transfer line becomes stagnant with no uniformity measurement carried out and working efficiency is very low.
To cope with this, respective rotary drums may be provided on each of the two transfer lines so that uniformity measurements of the two transfer lines are carried out independently. However, installation cost increases because two rotary drums are required.
The aforementioned rotary shaft for the tire is provided on a halfway position of the transfer line to support the tire by upper and lower rims and the rotary drum is positioned on lateral of the rotary shaft.
Sizes of the upper and lower rims for supporting the tire on the rotary shaft varies in accordance with kind of the tire, therefore exchange of the rims must be carried out as occasion demands. A method for supplying the rims is proposed by Japanese Laid-Open Patent Publication No. Hei 6-254989. According to this method, a plurality of mount conveyors arranged up and down like shelf stairs and enabled to go up and down are positioned along a transfer conveyor. On each of the mount conveyors are placed a pair of upper and lower rims of different sizes.
By setting a mount conveyor having required upper and lower rims placed thereon at the same height as the transfer conveyor, the required upper and lower rims can be shifted onto the transfer conveyor easily. Thus a pair of upper and lower rims of required size can be supplied selectively.
However, in the above Japanese Hei 6-254989, there is no description about recovery of the rim after use and it follows that the recovery is carried out by handwork. Namely, taking out the upper and lower rims detached from the rotary shaft and carrying the rims in a predetermined place or one of the above mount conveyors for storage are performed by workers with a large labor force.
Further, since each one rim supply apparatus is required for one tire uniformity machine, installation cost is increased.
Tires measured by a tire uniformity measurement apparatus are classified based on the result of the measurement to be used for various purposes. In a conventional tire transport and classification apparatus, tires after uniformity measurement are transported forward by a forward transport conveyor and transferred on a right-and-left transport conveyor at an end of the forward transport conveyor, then transported by the right-and-left transport conveyor to respective positions predetermined corresponding to kinds of the tire and taken out at the corresponding positions.
A number of kinds of tire into which the tires can be classified is generally determined by that how many tires can be arranged on the right-and-left transport conveyor leaving a space between them. For example, if three tires can be arranged on the right-and-left transport conveyor leaving a proper space between them, three kinds of tire can be classified, and hitherto such classification of about three kinds was general in view of installation space.
Tire measurement standards and tire performance judgment criterions set in a tire uniformity measurement apparatus has been dispersed widely according to tire size (rim diameter, tire width, flatness etc.), use and destination and kinds of tire tend to increase more and more in the future.
The classification of about three kinds of the customary transport classification apparatus can not cope with the above situation. If the right-and-left transport conveyor is made long, the number of kinds of tire into which the tires can be classified is increased, but a broader space is required for installing the apparatus so that space efficiency becomes low. In almost all lines of existing uniformity measurement apparatuses, there is no space for the increase and such a increase is very difficult.
The present invention has been accomplished in view of the foregoing, and an object of the present invention is to provide an apparatus for measuring and correcting uniformity of tires in which a transfer line does not stagnate because of uniformity correction of a tire and uniformity measurement and correction of tires can be carried out efficiently.
Another object of the present invention is to provide a rim exchange apparatus for the tire uniformity measurement and correction apparatus in which used upper and lower rims are returned to a original supply place automatically for recovering as well as new rims are supplied to the tire uniformity measurement place from the supply place, thereby full automation is possible and reduction of installation cost can be intended.
Further object of the present invention is to provide a tire transport and classification apparatus for the tire uniformity measurement and correction apparatus in which a number of kinds of tire into which the tires can be classified can be increased greatly with a small installation space.